Using Loki in Grafana

BETA: Querying Loki data requires Grafana’s Explore section. Grafana v6.x comes with Explore enabled by default. In Grafana v5.3.x and v5.4.x. you need to enable Explore manually. Viewing Loki data in dashboard panels is not supported yet, but is being worked on.

Grafana ships with built-in support for Loki, Grafana’s log aggregation system. Just add it as a datasource and you are ready to query your log data in Explore.

Adding the data source to Grafana

Open Grafana and make sure you are logged in.

In the side menu under the Configuration link you should find a link named Data Sources.

Click the Add data source button at the top.

Select Loki from the list of data sources.

NOTE: If you’re not seeing the Data Sources link in your side menu it means that your current user does not have the Admin role for the current organization.

Name

Description

Name

The datasource name. This is how you refer to the datasource in panels, queries, and Explore.

Default

Default datasource means that it will be pre-selected for new panels.

URL

The URL of the Loki instance, e.g., http://localhost:3100

Maximum lines

Upper limit for number of log lines returned by Loki (default is 1000). Decrease if your browser is sluggish when displaying logs in Explore.

Querying Logs

Querying and displaying log data from Loki is available via Explore. Select the Loki data source, and then enter a log query to display your logs.

Viewing Loki data in dashboard panels is not supported yet, but is being worked on.

Log Queries

A log query consists of two parts: log stream selector, and a search expression. For performance reasons you need to start by choosing a log stream by selecting a log label.

The Logs Explorer (the Log labels button) next to the query field shows a list of labels of available log streams. An alternative way to write a query is to use the query field’s autocomplete - you start by typing a left curly brace { and the autocomplete menu will suggest a list of labels. Press the enter key to execute the query.

Once the result is returned, the log panel shows a list of log rows and a bar chart where the x-axis shows the time and the y-axis shows the frequency/count.

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Log Stream Selector

For the label part of the query expression, wrap it in curly braces {} and then use the key value syntax for selecting labels. Multiple label expressions are separated by a comma:

Another way to add a label selector, is in the table section, clicking on the Filter button beside a label will add the label to the query expression. This even works for multiple queries and will the label selector to each query.

Search Expression

After writing the Log Stream Selector, you can filter the results further by writing a search expression. The search expression can be just text or a regex expression.